Electric ultrasonic toothbrush



Jan. 13, 1970 s. ROBINSON ELECTRIC ULTRASONIC TOOTHBRUSH 2 Sheets-Sheet 1 Filed Jan. 51, 1968 INVENTOR. SEYMOUR ROBINSON Jan. 13, 1970 s. ROBINSON ELECTRIC ULTRASONIC TOOTHBRUSH v 2 Sheets-Sheet 2 Filed Jan. 31, 1968 INVENTOR.

SEYMOUR ROBINSON United States Patent-O 3,488,788 ELECTRIC ULTRASONIC TOOTHBRUSH Seymour Robinson, Miami, Fla., assignor of fifty percent to Stanley M. Richardson, Miami Beach, Fla. Filed Jan. 31, 1968, Ser. No. 701,963 Int. Cl. A46b 13/04 US. Cl. 15-4 4 Claims ABSTRACT OF THE DISCLOSURE An electric ultrasonic toothbrush having a transducer assembly in the handle thereof which is adapted to drive liquid on and between the bristles of a brush applicator secured to the end of the handle when the transducer is connected to an electronic oscillator source of ultrasonic energy.

This invention relates in general to dental hygiene and more particularly to an ultrasonic toothbrush which will remove and prevent the formation of plaque or tartar on teeth.

Prior electric toothbrushes apply mechanically produced reciprocation motion to the bristles of a toothbrush at a relatively low frequency and in combination with a dentifrice will remove food particles and reduce the formation of plaque and calculus to a limited degree. It is well known that for proper tooth hygiene professional mechanical methods must be used periodically to scale the calculus from the teeth to maintain healthy gums.

The present invention greatly improves the above results and greatly reduces the periods of professional services required by the provision and use of an ultrasonic toothbrush, the bristles of which are adapted to carry saliva or the mixture of dentifrice and saliva, which carries ultrasonic oscillation to the surface of each tooth for the removal of plaque and calculus encrustations without injury to the enamel of the tooth.

A further object of the invention is the provision of an ultrasonic toothbrush which greatly reduces the time element in ordinary brushing by thoroughly removing trapped food particles between the teeth in addition to limiting the formation of calculus thereon.

These and other advantages in one embodiment of the invention are described and shown in the following specification and drawings, in which:

FIG. 1 is a perspective view of the ultrasonic toothbrush including an illustration of the electric ultrasonic generator therefor.

FIG. 2 is a fragmentary underside view of the brush shown in FIG. 1.

FIG. 3 is a side elevation taken through section line 3-3, FIG. 1.

FIG. 4 is a cross sectional end elevation taken through section line 44, FIG. 2.

FIG. 5 is a perspective top view of the detachable brush shown in FIG. 1.

FIG. 6 is a perspective view of the transducer assembly shown in FIG. 3.

FIG. 7 is a side cross section elevation of the transducer assembly taken through section line 77, FIG. 6.

FIG. 8 is a perspective exploded view of the toothbrush shown in FIG. 1.

Referring to FIG. 1, the electronic toothbrush comprises a hollow handle 1 having a closure cap 2 in the rear end thereof and a detachable brush type applicator 3 removably secured in the opposite end of the handle. An ultrasonic drive member 4 terminates in an oblique portion 5 which has the outer end thereof positioned for free movement within the confines of the brush, as shown.

3,488,788 Patented Jan. 13, 1970 An electronic oscillator and amplifier 6, preferably a solid state device, is adapted to be energized by a power cord assembly 7 from a common source of commercial A.C. electric power. The electric ultrasonic output in the order of 30 kilocycles is carried to the toothbrush by a pair of leads in a flexible cord 8. Well known adjustment means are provided to vary the frequency and ultrasonic electric out-put of the oscillator and amplifier 6.

Referring to FIG. 2, the brush applicator or head 3 is detachably secured in the handle 1 by means of a detent means comprising an open snap ring 9 retained in an inner peripheral groove in the handle, as shown, in FIGS. 2 and 3 in exaggerated size for the purpose of illustration. When the shoulder 10 of the applicator is inserted against the end of the handle then the snap ring 9 will engage a peripheral groove 11 in the applicator terminus which will removably retain the brush to the handle. An elongated slot 12 is provided in the body of the applicator which provides substantial clearance between the body and the drive member 4.

A resilient member 13 of uniform thickness, preferably made of rubber or other plastic or elastomer material, is secured by well known adhesive means over the top side of slot 12, as shown in FIGS. 3, 4, and 5.

FIG. 3 shows an electronic transducer element 14, of well known piezoelectric crystalin material, such as lead zirconite and barium titanate, which is secured to drive member 4 by rigid coupling 15, to be hereinafter described in detail. It is to be understood that other types of ultrasonic transducers, such as magneto striction devices will operate equivalent to the crystal variety shown. The outer electrode of the crystal is connected to the conductor 17 and the conductor 17 is connected to the inner end of the crystal, not shown.

It is to be noted that a longitudinal coaxial bore 18 in the brush applicator 3 is coaxial with the applicator terminus and junctions with the slot 12 therein, better shown in FIG. 3.

FIG. 6 shows the typical ceramic transducer element 14. The transducer is formed to oscillate in the direction shown by arrow with reference to the handle when energized by oscillating electric energy and because of the rigid coupling 15 between the transducer elements and the drive member 4. It is apparent that the latter will oscillate longitudinally with the end of element 14.

The cross section shown in FIG. 7 illustrates the coupling of the drive member 4 with the crystal element 14a by means of a disc 19 secured to the crystal element by brazing or epoxy adhesive means to which the inner end of the driving member 4 is centrally secured by similar means. A reinforcement cup 15, secured to element 14, is provided with a central aperture for the passage of the drive member 4, as shown.

Referring to FIG. 8, and to prevent improper orientation of the brush applicator with the drive member 4, a key 20, integral with the body of the brush applicator, is provided to engage a keyway 21 in the inner periphery of the handle 1 when the brush is assembled, as shown in FIG. 1.

In operation and under the assumption that the power cord 7 is connected to a source of energy and the oscillator-amplifier 6 is preadjusted then the drive member 4 will reciprocate at a predetermined ultrasonic frequency and amplitude. In use and when a dentifrice or liquid is applied to the bristles and the bristles are placed against the teeth, then the oblique portion 5 of the driver will excite the liquid between and surrounding the bristles with ultrasonic vibration at a forced vector due to the oblique end of the drive member 4. Thus the saliva and the mixture of the dentifrice therewith will impinge against the surface of the teeth at ultrasonic frequency and quickly remove food particles, plaque and calculus at relatively short periods of time.

It is to be noted that the vibration forces emanating from the rear side of the outer end drive member 4 is substantially absorbed by the resilient member 13 with the possible exception of components reflected toward the teeth and reinforcing the etfectiveness of the primary oscillation.

Having described my invention, I claim:

1. An electric ultrasonic toothbrush comprising means forming a hollow handle,

a toothbrush head detachably secured to said handle including a plurality of tufts of bristles of predetermined length projecting from one side thereof,

said head having an axial bore entering said handle joining an elongated slot centrally positioned between said bristles,

an ultrasonic transducer means secured in said handle adapted for axial ultrasonic motion at the output end thereof when energized at the input end thereof, 7

an elongated drive member secured to and extending from the output end of said transducer means through the said bore in said head and centrally positioned in said slot for ultrasonic longitudinal vibration therein,

a predetermined outer end portion of said drive member formed at a predetermined angle oblique with respect to the principal axis of said member toward said bristles for transmitting vectors of axial vibration forces in the member vibrating in a direction substantially normal to said member and substantially parallel said bristles,

a source of ultrasonic electric energy,

a pair of conductors connected to said source of energy and said input end of said transducer whereby said head when immersed in a liquid media ultrasonic vibration is transmitted from said driver means and along said bristles by said media when said transducer is energized by said source of energy.

2. The construction recited in claim 1 whereby a resilient member of predetermined thickness is marginally secured over said slot on the side of said head opposite said bristles for absorbing vectors of vibration forces radiating from the inner side of the outer end portion of said drive member.

3. An electric ultrasonic toothbrush comprising means forming a hollow handle,

a toothbrush head detachably secured to said handle including a plurality of tufts of bristles of predetermined length projecting from one side thereof,

said head having an axial opening entering said handle joining an elongated axial slot centrally positione between said bristles,

an ultrasonic polycrystal piezoelectric transducer means secured in said handle and adapted for ultrasonic motion at the output end thereof when electrically energized at the input thereof,

an elongated drive member secured to and extending from the output end of said transducer means and extending through said bore in said head and positioned centrally in spaced relation in said slot for ultrasonic longitudinal vibration therein,

a predetermined outer end portion of said drive member formed at a predetermined angle oblique with respect to the principal axis of said member toward said bristles for transmitting vectors of axial vibration forces in the member vibrating in a direction substantially normal to said member and substantially parallel said bristles,

a source of electric energy,

an electric ultrasonic generator means having an output and an input with the latter connected to said source of energy,

the said output of said generator connected by flexible conductors to the said input of said transducer means whereby said head when immersed in a liquid media ultrasonic vibration is transmitted from said driver means and along said bristles by said media when said generator is energized.

4. The construction recited in claim 3 including a detent for removably retaining said head to said handle comprising a cylindrical terminus integral with said head including a groove around the periphery thereof,

a bore in said handle for slidably receiving said cylindrical terminus,

said bore having a circular recess around the inner periphery thereof,

a compressible open ring retained in said recess whereby said groove in said terminus will engage said ring and removably hold said head on said handle.

References Cited UNITED STATES PATENTS 8/1967 Parisi et a1 1522 4/1968 Kuris et al 1522 X FOREIGN PATENTS 539,735 12/1931 Germany.

EDWARD L. ROBERTS, Primary Examiner U.S. Cl. X.R. 

